1. Field of the Invention
The present invention relates to an ink jet recording apparatus. More particularly, the invention relates to an ink jet recording apparatus capable of reading images, having an installation unit for installing an image reading head.
2. Related Background Art
Conventional printers are generally of such a type as to receive data from a computer and record data on a recording sheet in accordance with the contents of the data thus received. In recent years, however, there have been made available those printers provided not only with a printing function, but also with the function to read image data recorded on a recording sheet, such as are used for copying machine and facsimile equipment, among others. Complex type printers, which are capable of recording and reading, are increasingly in demand.
To meet with such demands, there have been proposed printers in which the image reading function is added to the recording function (as disclosed in the specifications of Japanese Patent Publication No. 1-20832, Japanese Patent Publication No. 2-21711, Japanese Patent Publication No. 2-21712, for example).
In any one of these publications, it is intended to make those functions possible by exchanging the head units for reading and recording, while sharing the sheet feeding system for both uses.
Meanwhile, as recording methods of a printer, the ink jet method takes the lead currently over the dot-impact, thermal transfer, electronic photography, and other methods. An ink jet printer is one that discharges liquid ink from the recording head to record on a recording sheet. The carriage having a recording head and an ink tank or an ink supply mechanism, such as ink supply tube, installed on it, is caused to travel in the scanning direction for recording on the sheet.
For an ink jet printer, a cap is provided to prevent the recording head from drying out, and also, to close the nozzle surface of the head in an air-tight manner so as to avoid any ink leakage from the recording head when recording does not occur. Here, in this respect, if dust particles clog the nozzles of the recording head or air enters them, defective recording may ensue. In order to recover them under such conditions, the aforesaid cap is provided with a recovery mechanism having a pump to suck ink by arranging a conductive connection between the pump and the cap.
FIG. 46 shows one structural example of the information processing apparatus provided with the conventional ink jet recording apparatus described above.
The printer unit 401 (recording apparatus) of the information processing apparatus 400 shown in FIG. 46 comprises an aperture 406a for use in cleaning the white reference; an aperture 406b for use in the exchanging operation; and an aperture 406c for use in jamming disposition. However, there is a trend to make the recording apparatus, serving as the printer unit 401 or the information processing apparatus and others using such recording apparatus smaller. The need for its portable use is increasing, making it necessary to provide a housing that provides a higher rigidity so that the apparatus withstands being carried around.
Also, for an ink jet printer of this kind, it is necessary to discharge ink from the ink discharge ports as a liquid. Therefore, the circumference of the recording head (ink jet recording head) tends to be wet due to the ink. It is inevitable that the circumference of the cap becomes wet when capping is conducted to cover the ink discharge ports of the recording head. Also, the fine droplets created separately from the discharged ink liquid or finely spreading droplets created when the ink liquid impacts upon a recording medium, that is, the so-called ink mist, tend to float in the space in the apparatus. Such ink mist often occurs in a larger quantity in the case of a color recording where plural kinds of color ink liquid are impacted one after another; where highly precise recording occurs in which fine ink droplets are impacted in high density; where high speed recording occurs in which the ink discharge is greater per hour; and where recording occurs by means of a small printer whose interior space is small accordingly.
When an image reading head, serving as functional elements to read images, is installed on a carriage or the like for an ink jet printer of the kind, it is found that the influence of ink as described above produces an adverse effect on the performance of the reading head. In other words, a problem is encountered that the quality of reading performance is lowered due to ink adhesion to the reading head and the member providing the white reference for color correction.
Also, it is found that particularly when a printer of a serial scanning type is employed, the unstable speed before the carrier (carriage) arrives at a constant speed produces an adverse effect on recording images or reading them for recording or reading images of the scanner (reading head) immediately after the carrier is caused to start traveling for recording or reading the images provided by a scanner. If any uneven component, especially resulting from such unstable speed, is included in the images read out by the scanner, there is encountered a problem that the quality of recorded images is conspicuously degraded by the presence of such an uneven component that may be combined with the further unevenness occurring at the time of recording.